1. Field of the Invention
The present invention relates to a system and method for providing simultaneous multiple push-to-talk (PTT) over cellular (PoC) multimedia service.
2. Description of the Related Art
Significant developments in mobile communications technology and the extension of mobile communications networks have resulted in the development of a vast array of services and applications for use with a cellular phone.
Concurrently, there is an increasing demand from cellular phone users for additional services, such as a location, a multimedia, and a push-to-talk (PTT) service. Among these additional services, the PTT service supports various supplementary functions such as an instant messenger function and a status display, as well as a group call and a voice call which are also provided by an existing radio or a trunk radio system (TRS).
Currently, standardization of a PoC service which utilizes the PTT function in a mobile communication network is actively proceeding. One unique feature of the PoC service that differs from existing mobile communication services is that a user can participate in a plurality of PoC sessions, and so can use a call service while moving among the PoC sessions as needed. A requirement that the user should be able to use the call service while moving among the plurality of PoC sessions is specified in the Open Mobile Alliance (OMA), which is a forum for specifying mobile communications services.
Meanwhile, a current PoC system supports a multimedia communication service. To this end, the PoC system defines video, images, text, voice, etc. as a new type of multimedia. Further, the current PoC system can display a multistream (e.g. video or images) owing to improved performance of terminals.
However, the current PoC system is not capable of simultaneously transmitting a plurality of multimedia streams to a terminal during a multisession.